RF wireless remote security systems have one or more radio frequency (RF) channels to receive signals from remote sensors, each of which is equipped with an RF transmitter. The remote sensors may be such things as glass break detectors (for burglary protection), smoke detectors (for fire detection) and passive infrared motion detectors (for burglary protection). Each sensor uses a discrete RF channel to communicate with the central processing unit (CPU) of the security system. When the remote condition-responsive sensor is triggered, it transmits an RF pulse over its associated RF channel to the CPU. A receiver in the CPU detects the RF pulse and, depending on the channel, may initiate one or more control functions. For example, the CPU may activate a burglar alarm or fire alarm either locally or at a central station. In addition, for burglary protection, the CPU may turn on premises lighting. The CPU may also activate a pre-programmed automatic telephone dialer for dialing a police or fire department, or any other telephone number.
More sophisticated wireless security systems are also arranged to respond to medical emergencies. The CPU may be arranged to accept an RF signal from a bedside transmitter or a transmitter worn around the neck of a patient. When the patient signals a medical emergency by activating his transmitter, the CPU may activate lights, a remote alarm or an automatic telephone dialer.
The CPU can also be used to remotely control premises lighting over existing AC line wiring. For example, by using a wireless hand held remote control transmitter, an RF pulse can be sent to the CPU from virtually anywhere in the premises to turn on lights by remote control. In this case, the CPU sends a control signal over the AC line wiring to a receiver with a switch to control the lighting. The switch is activated in response to the signal sent over the AC line wiring from the CPU.
Typical security systems, however, do not provide for control of premises heating, ventilating and air-conditioning (HVAC) equipment. Heretofore, premises HVAC have been controlled by closed systems separate from any premises security system. It would be advantageous to the users of the security system to include the HVAC control with the premises security system. Accordingly, there is a need for a premises security system which provides not only burglary and fire protection, but environmental control of the premises as well.
It would also be advantageous to provide back-up or "fail safe" operation of the remote sensors. The present invention achieves these advantages in a novel and unobvious manner and without appreciably increasing the complexity or cost of the wireless security system, and without requiring an increase in channel capacity.